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From:   David Edmondson <david.edmondson@oracle.com>
To:     linux-kernel@vger.kernel.org
Cc:     Jim Mattson <jmattson@google.com>, Borislav Petkov <bp@alien8.de>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Wanpeng Li <wanpengli@tencent.com>,
        Ingo Molnar <mingo@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        David Matlack <dmatlack@google.com>, x86@kernel.org,
        kvm@vger.kernel.org, David Edmondson <david.edmondson@oracle.com>
Subject: [PATCH v4 4/4] KVM: x86: SGX must obey the KVM_INTERNAL_ERROR_EMULATION protocol
Date:   Fri, 13 Aug 2021 08:12:11 +0100
Message-Id: <20210813071211.1635310-5-david.edmondson@oracle.com>
In-Reply-To: <20210813071211.1635310-1-david.edmondson@oracle.com>
References: <20210813071211.1635310-1-david.edmondson@oracle.com>
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When passing the failing address and size out to user space, SGX must
ensure not to trample on the earlier fields of the emulation_failure
sub-union of struct kvm_run.

Signed-off-by: David Edmondson <david.edmondson@oracle.com>
---
 arch/x86/kvm/vmx/sgx.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
index 6693ebdc0770..35e7ec91ae86 100644
--- a/arch/x86/kvm/vmx/sgx.c
+++ b/arch/x86/kvm/vmx/sgx.c
@@ -53,11 +53,9 @@ static int sgx_get_encls_gva(struct kvm_vcpu *vcpu, unsigned long offset,
 static void sgx_handle_emulation_failure(struct kvm_vcpu *vcpu, u64 addr,
 					 unsigned int size)
 {
-	vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-	vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
-	vcpu->run->internal.ndata = 2;
-	vcpu->run->internal.data[0] = addr;
-	vcpu->run->internal.data[1] = size;
+	uint64_t data[2] = { addr, size };
+
+	__kvm_prepare_emulation_failure_exit(vcpu, data, ARRAY_SIZE(data));
 }
 
 static int sgx_read_hva(struct kvm_vcpu *vcpu, unsigned long hva, void *data,
@@ -112,9 +110,7 @@ static int sgx_inject_fault(struct kvm_vcpu *vcpu, gva_t gva, int trapnr)
 	 * but the error code isn't (yet) plumbed through the ENCLS helpers.
 	 */
 	if (trapnr == PF_VECTOR && !boot_cpu_has(X86_FEATURE_SGX2)) {
-		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
-		vcpu->run->internal.ndata = 0;
+		kvm_prepare_emulation_failure_exit(vcpu);
 		return 0;
 	}
 
@@ -155,9 +151,7 @@ static int __handle_encls_ecreate(struct kvm_vcpu *vcpu,
 	sgx_12_0 = kvm_find_cpuid_entry(vcpu, 0x12, 0);
 	sgx_12_1 = kvm_find_cpuid_entry(vcpu, 0x12, 1);
 	if (!sgx_12_0 || !sgx_12_1) {
-		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;
-		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;
-		vcpu->run->internal.ndata = 0;
+		kvm_prepare_emulation_failure_exit(vcpu);
 		return 0;
 	}
 
-- 
2.30.2